1. Field of the Invention
The invention relates to connection of a semi-rigid coaxial cable provided with a single-core inner conductor in a high-frequency connection.
2. Description of the Related Art
Many electrical units, such as filters used in radio systems, must be tuned and tested before actually taken into use. It is thus necessary that in order to be tested, such a unit, component or machine part can be connected to a testing apparatus reliably and in an electrically similar way as to the circuit board of the actual system. This is especially important when high frequencies are applied. Between the units, components and machine parts there is often a coaxial cable, the other end of which is connected to the testing apparatus during testing, and when the unit is combined with a desired system, the end of the coaxial cable that was connected to the testing apparatus during testing is connected to the circuit board of the system.
However, it is not entirely uncomplicated to connect the coaxial cable to the testing apparatus and to the circuit board of the actual system, and thus a variety of supplementary parts are required for the connection, particularly when simple and inexpensive cable fasteners are to be used instead of expensive and large connectors. In a test measurement, a coaxial cable can be fastened by means of a separate fastener, for instance, to a test jig, which comprises a connector for connecting the testing apparatus. The coaxial cable is fastened similarly to the circuit board of the actual product as well. This solution is associated with many problems. A test measurement requires a separate test jig with connectors, which hinders the measurement and increases costs. In addition, the inner conductor of the coaxial cable must be soldered to the test jig and the earth conductor must be pressed to the test jig by screwing, for instance. Soldering is, however, a slow procedure. A separate test jig also produces differences between the connection of the test measurement and the circuit board connection during the actual use. This weakens the reliability of the measurement and affects the high-frequency properties of the system.
It is an object of the invention to provide a connection method and a connection arrangement implementing the method in such a manner that it is easier to carry out the connection to the testing environment and the reliability of the testing improves. This is achieved by a connection method intended for a high-frequency connection of a semi-rigid coaxial cable provided with a single-core inner conductor. The method further uses an adapter fastener, which is intended for both an adapter connection and a circuit board connection, the adapter fastener being electrically conductive; the adapter fastener comprises a hole which extends through the adapter fastener and to which the coaxial cable is fixed; the sheath of the coaxial cable is electrically connected to the adapter fastener and a male connection is formed at the adapter fastener by means of the inner conductor of the coaxial cable; in the adapter connection, the male connection is connected to a female connection of a standardized adapter by connecting the inner conductor of the coaxial cable electrically to a female contact of the standardized adapter and by connecting the adapter fastener electrically by means of adapter protrusions to the frame of the standardized adapter; and in the circuit board connection, the adapter fastener is fastened by means of circuit board protrusions to a circuit board and the adapter fastener is connected electrically by means of the circuit board protrusions to the earth of the circuit board; and the inner conductor of the coaxial cable, used in the male connection, is connected electrically to a desired electrical conductor of the circuit board.
The invention also relates to a connection arrangement arranged to be used for a high-frequency connection in a coaxial cable comprising a single-core inner conductor. The arrangement further comprises an adapter fastener intended for both an adapter connection and a circuit board connection; the adapter fastener comprises a hole which extends through the adapter fastener and to which the coaxial cable is fixed; the sheath of the coaxial cable is electrically connected to the adapter fastener and a male connection is formed at the adapter fastener by means of the inner conductor of the coaxial cable; for the adapter connection, the male connection is formed at a female connection of a standardized adapter and the inner conductor of the coaxial cable is arranged to be connected to a female contact of the standardized adapter; and the adapter fastener comprises adapter protrusions for fastening the adapter fastener to the standardized adapter and connecting the adapter fastener electrically to the frame of the standardized adapter; and for the circuit board connection, the adapter fastener comprises circuit board protrusions for fastening the adapter fastener to a circuit board and connecting the adapter fastener electrically to the circuit board; and the inner conductor of the coaxial cable, used in the male connection, is arranged to be connected electrically to the circuit board.
Preferred embodiments of the invention are disclosed in the dependent claims.
The invention is based on providing an end of a coaxial cable with an adapter fastener, at which a male connection from the inner conductor of the coaxial cable is formed for an adapter and circuit board connection.
The method and connection arrangement of the invention provide a plurality of advantages. The test measurement and connections between the system parts can be simplified and costs can be reduced. Also the reliability of the connection improves.